Non-lethal weapons are designed to incapacitate the target, and when properly used do not result in any injuries, fatalities or after effects. Non-lethal weapons in the form of aerosol sprays capable of temporarily incapacitating a target have shown great use both for enforcement and defensive purposes. These non-lethal sprays are particularly useful in close proximity encounters, such as breaking up a bar fight or intervening in a domestic disturbance; stopping fleeing suspects; in hostage or terrorist situations; in barricade situations, where the subject is violent, but has not taken a hostage; and generally in crowd control or riot situations.
Aerosol sprays commercially available are of three types: chloroacetophenone (CN) commonly known as mace, orthochlorobenzylidenemalononitrile (CS) commonly known as tear gas, and oleoresin capsicum (OC) also known as pepper spray. Both mace and tear gas are lachrymators that cause tearing and irritation. However, they have no effect on those who are enraged or are under the influence of narcotics, or alcohol. Pepper sprays contain an extract of hot pepper and act as an inflammatory agent causing closing of the eyes and coughing.
Initial aerosol type formulations were of the lachrymator type, such as Chemical Mace® lachrymator, included various types of liquid based CN chemical formulae in pressurized aerosol spray containers. However, the lachrymator agents used in such sprays contain highly toxic and/or cancer causing chemicals. Furthermore, such technology used environmentally unfriendly carrier agent/solvents such as trichlorotrifluoroethanes (CFC's 111, 113) and cosmetic kerosene.
In an effort to overcome these problems, a pepper based inflammatory spray technology was developed and first introduced through the CAP-STUN® brand pepper spray in 1982 introduced into the self-protection market. Pepper sprays are available with various concentration of capsaicin (capsaicinoids), which is the primary ingredient producing the effects of pepper spray. Various types of pepper sprays have since come into existence; however, the technology of pepper spray is still basically unchanged since its inception.
Even though pepper sprays and other lachrymators are generally effective for self-defense purposes, improvements are still desired, particularly in decreasing the time it takes for incapacitation of the recipient and increasing the length of time for incapacitation while avoiding long term effects on the target. Law enforcement officials would like to be able to incapacitate a suspect for a sufficient time to allow immobilization and/or transport to an appropriate holding facility. Thus, efforts have been made to increase effectiveness or duration of the pepper spray by increasing the amount of pepper in the spray. However, this has been limited by the need to avoid permanent harm or injury to the recipient, particularly damage to the eyes, skin, or upper respiratory tract. This has left unmet the need for a more effective and longer duration spray that can be used without long-term harm to the recipient, while reducing or eliminating any impact on the user and any bystanders, and reducing any adverse effects on the environment.
Another problem with the pepper sprays and other lachrymators dispensed using an aerosol or other spray dispensing system is that when it is dispensed, there is always the possibility that an open flame or other source of ignition may be present that could ignite the solvent or carrier of the mixture resulting in serious bodily harm to both the user and the intended recipient of the lachrymator. Examples of some possible sources of ignition include lit cigarettes or cigars, burning candles or matches, and stoves or other heating devices.
In particular, alcohol-based or containing sprays pose a considerable risk of ignition. However, replacing the alcohol cannot simply be replaced with water since the active ingredients are not soluble therein and thus an additional solubilizing agent must be used—most of which also exhibit flammable tendencies.
Foam based carrying agents also may potentially cause gagging, vomiting and choking from entry of foam bubbles in the respiratory system. Chlorinated solvents such as CFC's, HCFC's and HFC's can be damaging to the eyes as well as to the environment.
There are a number of household and industrial aerosol and other spray device propellant and solvent formulations currently available. Known nonflammable carriers, although less likely to ignite when exposed to such sources of ignition, pose their own problems. Many are classified as carcinogenic, and thus are not suitable for use where there is skin contact. Most are as ozone depleting and fail to meet applicable standards for ozone depletion and volatile organic compound (VOC) emissions.
Due to the self-pressurized nature of aerosols and the direct correlation between pressure, temperature and volume, extreme temperature variance is an area of concern. Particularly desirable aerosols must be capable of operating even when exposed to high temperatures, such as in a parked car in the summer, and also be functional when the temperature falls below zero. Those solvents that don't thicken and freeze, such as hydrocarbons and alcohols, are generally flammable. Exposure to extreme elevated temperatures can cause instability of the spray pattern while exposure to sub-zero temperatures can freeze the formulation and render the system inoperable.
Another area of concern, particularly where irritating chemicals are being sprayed, is the ability to reliably direct the spray to an intended target and not have it remain airborne for extended periods of time. When used indoors, many sprays can remain airborne too long, thus affecting bystanders, further circulating into the heating or air conditioning system, and contaminating other areas. When used outdoors, many sprays can be blown back to the face of the user or more erratically with wind direction and contaminate bystanders rather than the intended target. Furthermore, prior art sprays have had difficulty in penetrating rain, and thus have not been able to reach their desired target when used in such conditions.
Other problems arise with defense spray applications, such as in pepper sprays and mace, where the spray is directed to the facial area. Here the solvent formulation requirements are stricter since they are intentionally sprayed on an individuals face, with exposure to eyes, skin and the respiratory system. Therefore, the solvent formulation should also pass toxicological tests showing no damage to the eyes, skin or upper respiratory tract. Furthermore, the solvent formulation must be miscible with the active ingredients in the defense spray.
Prior art solvent systems have proven unsuitable for application due to a number of problems including flammability, toxicity, carcinogenic properties, irritant, adverse reactions with materials contacted, and inability to dissolve and maintain in a dissolved state the active ingredient. Furthermore, known solvents that are non-toxic when used in an aerosol dispensing system lack the ability to be readily controlled and directed, particularly in windy and/or rainy conditions.